This OLCC programming example page demonstrates getting a Chemical Abstracts System Registry Number from NIST WebBook using JavaScript.

Note that this query requires a proxy, as the NIST Webbook does not allow cross-origin AJAX
It uses web page "scraping" to find the desired information within HTML.

Press the "test" button to evaluate the JavaScript in the textarea below.
Feel free to modify the JavaScript and press test again.

var name = "butanoic acid" var url = "http://webbook.nist.gov/cgi/cbook.cgi?Units=SI&Name=" + encodeURIComponent(name); // Send this url to the proxy, which just returns the HTML code of the page. url = "https://chemapps.stolaf.edu/jmol/jsmol/php/jsmol.php?query=" + encodeURIComponent(url); $("#url").html(url); $.get(url, function(data){ $("#rawhtml").html(data.replace(/\</g,"&lt;").replace(/\n/g,"<br>")); // Get the text that is the second XML element in the li tag containing "CAS Registry Number:" $("#result").html($(data).find("li:contains('CAS')").contents().eq(1).text().trim()); });


url:
result:
raw HTML: